A rechargeable battery such as a lithium ion battery as an electricity storage device that stores power supplied to an electric motor used as a drive source is mounted on a vehicle such as an electric vehicle (EV) and a plug-in hybrid vehicle (PHV).
Patent Document 1 discloses such a type of the rechargeable battery, for example. As shown in FIG. 9, a rechargeable battery 50 of Patent Document 1 is configured such that a case 51 accommodates an electrode assembly 52 and terminal members 53 are connected to the electrode assembly 52. The electrode assembly 52 includes negative electrodes 54, in each of which negative electrode active material layers 54b are applied to a metal foil 54a, and positive electrodes 55, in each of which positive electrode active material layers 55b are applied to a metal foil 55a. The electrode assembly 52 is configured to be stacked such that a separator 56 is located between each adjacent pair of the negative electrodes 54 and the positive electrodes 55. In the electricity storage device including the rechargeable battery 50 as in Patent Document 1, a tab, which is a region free from the active material, is formed on each of the metal foil 54a of each negative electrode 54 and the metal foil 55a of each positive electrode 55. The tabs are bundled as tab groups and connected to the terminal members 53. The tab groups each include a bent portion, which is curved or bent, and an extending portion, which extends from the bent portion in the stacking direction of the electrode assembly 52. The extending portion contacts and is connected to the corresponding terminal member 53.